Subgenus 2. _Petalospyrella_, Haeckel. _Definition._--Basal plate with three large collar pores (two paired posterior cardinal, and an odd anterior sternal pore). 3. _Petalospyris triomma_, n. sp. (Pl. 87, fig. 14). Shell nut-shaped, tuberculate, with sharp sagittal stricture and irregular roundish pores. Basal plate with three large pores and three alternate smaller. Apical horn stout, conical, half as long as the shell. Twelve to fifteen feet, divergent, curved, pointed, as long as the horn. _Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.03 long. _Habitat._--North Pacific, Station 244, depth 2900 fathoms. 4. _Petalospyris platyacantha_, Ehrenberg. _Petalospyris platyacantha_, Ehrenberg, Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 80, Taf. xxii. fig. 8. Shell campanulate, smooth, with slight sagittal stricture and small irregular roundish pores. Basal plate with three large pores (?). Apical horn very strong, three-sided pyramidal, twice as {1061}long as the shell (its edge is described by Ehrenberg as a "canaliculus.") Feet ten to twelve, flat, triangular, vertical, about as long as the shell. _Dimensions._--Shell 0.04 long, 0.05 broad; 0.07 long, feet 0.03 long. _Habitat._--Fossil in Barbados. 5. _Petalospyris corona_, Stöhr. _Petalospyris corona_, Stöhr, 1880, Palæontogr., vol. xxvi. p. 98, Taf. iii. fig. 13. Shell nut-shaped, smooth, with slight sagittal stricture and very numerous small circular pores; on each side of the stricture three larger annular pores (the undermost the largest). Basal plate with three large pores only. Apical horn very small, conical. Feet twelve to eighteen, short conical, nearly vertical, shorter than the half shell (in my specimen from Caltanisetta much stouter than in that of Stöhr). _Dimensions._--Shell 0.07 long, 0.09 broad; horn and feet 0.01 to 0.03 long. _Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). Subgenus 3. _Petalospyrissa_, Haeckel. _Definition._--Basal plate with four collar pores (two larger posterior cardinal and two smaller anterior jugular pores). 6. _Petalospyris octopus_, n. sp. (Pl. 87, fig. 11). Shell nut-shaped, tuberculate, with sharp sagittal stricture and irregular, roundish pores. Basal plate with four larger pores. Horn slender, conical, half as long as the shell. Feet eight, very slender, about three times as long as the shell, subvertical, with outer convex edge and convergent ends. _Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.03 long, feet 0.2 long. _Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. 7. _Petalospyris eupetala_, Ehrenberg. _Petalospyris eupetala_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 80, Taf. xxii. fig. 4.